How deeply does The Well-Grounded Rubyist, Fourth Edition cover methods?

Explains returned symbols, sorting, filtering, singleton methods, inheritance, and modules, but defers broader method lookup details.

Methods

As explained in The Well-Grounded Rubyist, Fourth Edition

methods is a Ruby method that returns an array containing the names of methods available to an object.

Ruby’s methods method returns an array of symbols naming the methods an object can call. Sorting the result makes a large capability list easier to browse. section 2.3 section 15.2.1

A methods query includes:

Methods inherited through the object’s ancestry. section 7.7.1
Methods supplied by included modules, even when inclusion happens after an object exists. section 7.7.1
Singleton methods defined specifically for that object. section 7.7.1
For class and module objects, methods callable on the class or module itself—not methods available to their instances. section 7.7.1

Filtering a capability list

Given string = "Test string", string.methods.grep(/case/).sort finds case-related names such as :downcase, :swapcase, and :upcase. The returned symbols can be filtered, sorted, and compared to answer questions about an object’s capabilities. section 15.2.1 section 15.2

>> "I am a String object".methods.sort

Inspecting and sorting a real String object’s method names makes the returned array and its scale visible. section 7.7.1

How The Well-Grounded Rubyist, Fourth Edition covers it

Cover of The Well-Grounded Rubyist, Fourth Edition

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Related concepts

methodmeasures · A method is a callable operation associated with an object or type and invoked through that association.
symbolproduces · A symbol is a name or sign that represents or identifies a value, entity, operation, or concept within a notation or system.
Objectuses · java.lang.Object is the root class of Java’s reference-type hierarchy and defines methods inherited by Java reference types.
public methodproduces · A public method is a method that code outside its defining class, type, or component can invoke through the language's ordinary access mechanism.
instance_methodsequivalent to · instance_methods is a Ruby Module method that returns the public and protected instance methods available from a class or module, optionally including inherited and included methods.

This explainer was generated by Manning's knowledge graph from the text of The Well-Grounded Rubyist, Fourth Edition. The section links point to the parts of the book it draws on.